Sigilyph @ Focus Sash
Ability: Magic Guard
EVs: 16 HP / 252 SpA / 240 Spe
Timid / Modest Nature
- Psyshock
- Heat Wave
- Energy Ball
- Calm Mind
Sigilyph is fast, can set up and sweep late game, and gets Magic Guard, so this set seems somewhat intuitive. Magic Guard ensures Focus Sash is kept intact, so you can come in late game, be guaranteed to live a hit, and possibly CM to clean up. Psyshock, Heat Wave, Energy Ball for solid coverage, EVs and Nature can be tweaked to your liking.